Four-point hydraulically operated press



Jan. 11, 1938. I. PATRICK FOUR'POINT HYDRAUIJICALLY OPERATED PRESS Filed June 15, 1934' 3 Sheets-Sheet l A TTORNE y:

Jan. 11, 1938. p c 2,105,053

FOUR-POINT HYDRAULICALLY OPERATED PRESS Filed June 15, 1954 3 Sheets-Sheet 3 A TTORNE Y Patented Jan. 11, 1938 UNITED STATES PATENT OFFICE Isaac Patrick, Mount Gilead, Ohio, assignor, by

mesne assignments,

to The Hydraulic Press Corporation, Inc., Wilmington, Del., a corporation of Delaware Application June-15, 1934, Serial N... 730,822

4 Glaims.

This invention relates to presses and, in particular, to presses operated by mechanical linkages.

One object of my invention is to provide a press having mechanical linkages interconnecting the platen and the power supply, this power supply comprising a hydraulic piston.

Another object is to provide a hydraulic press having linkages applying power to four points on the platen, and receiving power from a hydraulic piston.

Another object is to provide a press of this type, wherein the linkage is actuated by bell cranks pivotally mounted on the frame, these bell cranks being in turn actuated by a hydraulic piston-andcylinder assembly.

In the drawings:

Figure 1 is a diagrammatic front elevation partly in section, of the press of my invention;

Figure 2 is a front elevation of half of the press shown in Figure 1, showing the hydraulic circuit and valve for operating the press;

Figure 3 is a detailed side elevation of the operating lever of the press;

Figure 4 is a central vertical section through the press along the line 4-4 of Figure 1;

Figure 5 is a vertical section along the line 5-5 of Figure l.

Hitherto hydraulic presses have been used where great pressure is to be applied, and by this means the application of the pressure is controllable within accurate limits. A hydraulic press, however, as used in the prior art has been slow in its action and consequently at a disadvantage in the performance of modern high speed production operations. The mechanical press wherein the platen is operated through cranks and/or levers, has a high speed of operation, but its motions are not controllable because the crank must make a complete revolution hence the platen executes a complete stroke without possibility of any change in the high speed operation thereof. The mechanical press, however, has a rapid but a harsh and uncontrollable action which makes it unsuitable for delicate mechanical operations of forming parts liable to buckle or wrinkle in an undesired way if the pressure is not accurately and suitably applied.

The present invention seeks to combine the advantages of the hydraulic press with those of the mechanical press and yet eliminate the defects of both. In other words, the press of my invention by utilizing hydraulic means for supplying the force yet mechanical means for applying it to the platen, gives the controllability a (Cl. 100'l0) delicacy of operation of the hydraulic press, yet with a speed of operation comparable to the allmechanical press, at the same time avoiding the harshness of operation and uncontrollability of the latter. At the same time, the press of my invention avoids the complex and intricate lever and crank systems which have heretofore been utilized to control the application of pressure by purely mechanical means.

"Referring to the drawings in detail, Figure 1 shows a press having a frame, generally designated I, with side members 2, and lower and upper cross members 3 and 4 respectively. On the vertical members 2 are machined guideways 5 relative to which slides a platen, generally designated 6, having retaining plates I mounted thereon and adapted to maintain the platen 6 in proper relationship to the guideways 5. The lower cross member 3 and the platen I5 are provided with machined surfaces I and 8 respectively and recesses 9 therein suitable for the connection of dies or work pieces.

The platen near its four points is provided with four bores Ill, which receive four adjusting shafts II movably anchored thereto by the nuts I2, threaded on to the shafts II. The latter on their upper ends are provided with yokes I3, these yokes being interconnected by tie rods I4 secured thereto by the nuts I5 threaded on to the ends of the tie rods I4. In this manner the adjusting shafts II and the yokes I3 are similarly interconnected with one another, so as to give a rigid construction.

Each yoke I3 is pivotally connected, as at I6, to a link H, which at its opposite end is pivotally connected to a cross member I8 leading to one arm of a bell crank I9. Each bell crank I9 is pivotally mounted upon a shaft 20, which is secured to the projecting boss 2| of the frame cross member 4. The other arm of each bell crank I9 is pivotally connected, as at 22, to a connecting link 23, the other end of which is pivotally connected to a piston rod yoke 24, as at 25. By the term bell crank" the applicant means a lever, whose two arms form an angle, having its fulcrum at the apex of the angle.

The piston rod yoke 24 has a bore 26, which encircles the reduced portion 21 of a piston rod 28 and is held against the enlarged portion 29 thereof by the collar 30, threaded on to the lower end thereof. The piston rod 28 passes through the adjustable packing 3| into the interior of the hydraulic cylinder 32, having a cylinder head 35. The latter is provided with a port 33, whereas the side walls of the cylinder 32 are provided with a port 34 near the lower end of the cylinder bore 38. The piston rod 28 is provided with a piston head 31, which reciprocates within the cylinder bore 38. The entire cylinder-and-piston assembly is mounted in the countersunk portion 88 by the bolts 38, securing the flanged portion 48 therein.

The hydraulic circuit for operating the hydraulic cylinder to cause the platen 8 to rise and fall may be of any suitable kind, as may be desired for the particular conditions under which the press is designed to operate. One such circuit is shown in Figure 2, but it is understood that the invention is not restricted to the use of this particular circuit, which is shown for illustra tive purposes only.

The hydraulic circuit, shown in Figure 2, consists of the operating lever 58, which is pivotally supported, as at 5|, upon the bracket 82 secured to the side member 2 of the press, as at 58. The operating lever 58 has a bell crank portion 54 (Figure 3), pivotally connected by the link 55 and the pivot pins 58 and 51 to the valve connecting rod 58. The latter is connected to the reciprocable valve member 58, which is mounted to reciprocate within the bore 88 of the valve chamber 8|.

The valve member, generally designated 58, consists of the three spaced heads 82, 88, and 84, joined by the connecting neck 85, havingthe longitudinal bore 88 and transverse bores 81 and 88 therethrough. The valverchamber 8| is provided with suitably disposed ports 69, 10, ll, 12, 13, and 14. The ports 12, 18, and 14 are connected to the conduit 15, leading to the tank 18 forming the fluid supply for the hydraulic pump 11. The port 1| is provided with the conduit 18, leading to the lower port 34 in the hydraulic cylinder 32 (Figure 2), whereas the port 88 has the conduit 19, leading to the upper port 88 thereof. The conduits 18 and 18 are provided with the high pressure relief valves 88 and 8| respectively, these being designed to discharge the fluid therein through the relief conduits 82 and 83 into the conduits 15, leading to the tank 18, when the pressure within the conduits 18 or 19 exceeds'the predetermined pressure for which the relief valves 88 and 8| are designed to be released. The port 18 of the valve chamber 8| is connected by the conduit 84 to the outlet or pressure side of the pump 11, the intake or suction side being connected by the conduit 85 to the fluid supply in the tank 18.

In operation, the valve member 58 is shown in its neutral position in Figure 2. When the operator faces the press (Figure 2) and pulls the operating lever 58 toward himself, the valve member 59 rises in the valve chamber 8|. The head 82 then uncovers the port 69, and the head 84 uncovers the port 1|. Pressure fluid then flows from the pump 11 through the conduit 84 and the port 18 into the valve bore 88, thence out through port 89 and along the conduit 19 through the port 33 into the hydraulic cylinder 32. This causes pressure fluid to be applied to the upper side of the piston head 31. The lattermoves downward, forcing the fluid beneath, it out through the port 34, the conduit 18, and the port 1| into the lower part of the valve bore 68. This fluid passes out through the port 12 therein,

, and returns to the tank 18 by way of the conduit When the piston head 31 moves downward, it likewise moves the yoke 24 downward, and the oblique links 23 move the pivot pins 22 outward.

This motion, when transmitted to the bell cranks l8 and the toggle links H, causes the platen 8 to move downward, operating the dies or compressing the work pieces in the manner desired.

To reverse the press, the operator pushes the operating lever 58 away from himself, thus lowering the valve member 58. This causes the valve head 82 to uncover the port 88 and the valve head 84 to uncover the port 1|. Pressure fluid then flows from the pump 11 through the conduit 84 and the port 18 into the middle portion of the valve bore 88, thence through the bores 88, 81 and 88 ofthe valve member neck 85, and out through the port 1| and the pipe line 18. The latter conveys the pressure fluid to the cylinder bore 88 of the hydraulic cylinder 32 by way of the port 84, situated below the piston head 81 thereof. This moves the latter upward, forcing the fluid above it out through the port 88, and the conduit 18 into valve bore 88 by way of the port 88. The fluid thus passes into the upper part of the valve bore 88 and out through the port 14 into the conduit 15, whence it returns to the tank 18. In this manner, the platen 8 is caused to move upward, and the operation of the press is thereby reversed.

When the platen reaches a downward position, wherein it is exerting a predetermined pressure, the relief valve 8| opens, discharging the excess fluid into the relief conduit 88 and thence into the tank 18. This prevents overloading and damage to the press or to the work articles. Similarly, the relief valve 88 serves to release the pressure fluid when the press has been reversed and the platen reaches its topmost position, the excess fluid being discharged through the relief conduit 82 and the conduit 15 into the tank 18.

It will be understood that I desire to comprehend within my invention such modifications as may be necessary to adapt it to varying conditions and uses.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In combination in a press, a frame, a movable platen, links pivotally attached to said movable platen near the four comers thereof, a pair of bell cranks operatively connected to said links and pivotally mounted on said frame, and a hydraulic piston-and-cylinder assembly disposed between said bell cranks and operatively connected to said bell cranks, said bell cranks and said piston being arranged in substantially the same plane.

2. In combination in a press, a frame, a movable platen, links pivotally attached to said movable platen near the four comers thereof, a pair of bell cranks operatively connected to said links and pivotally mounted upon said frame, a hydraulic piston and-cylinder assembly disposed between said bell cranks and operatively connected to said bell cranks, said bell cranks and said piston being arranged in substantially the same plane, and transversely disposed members interconnecting each bell crank and each pair of links to form said operative connection, each member comprising a cross shaft having end connections with said links and an intermediat connection with said bell crank.

3. In combination in a press, a. frame having a top member, a movable platen, links pivotally attached to said movable platen near the four corners thereof, a pair of bell cranks operatively connected to said links and pivotally mounted upon said top member, and a hydraulic piston-andcylinder assembly disposed between said bell cranks and operatively connected to said bell cranks, said bell cranks and said piston being arranged in substantially the same plane.

4. In combination in a press, a frame having a top member, a movable platen, links pivotally attached to said movable platen near the four corners thereof, a pair of bell cranks operatively connected to said links and pivotally mounted upon said top member, said bell cranks having inwardly directed arms, a hydraulic piston-andcylinder assembly disposed between said bell cranks and operatively connected to the inwardly directed arms of said bell cranks, said bell cranks and said piston being arranged in substantially the same plane, and transversely disposed members interconnecting each bell crank and a pair of said links to form said operative connection. ISAAC PATRICK. 

